[Fix] File Manager can't access SD card on Lineageos rom

If you installed lineage os rom 14.1 and when you trying to access external sd card I get error: "can't access try with advanced root permission" even if root access is enabled and root is accessible.

How to Fix Common Bugs Lineage OS line no sd card error, alarm bug, Google play server error.lineage os: CyanogenMod was the biggest, most widely used custom Android ROM. Now, it has been discontinued, due in part to internal conflicts within Cyanogen Inc. A new fork of CyanogenMod called Lineage OS is taking up the mantle, and it will keep most of what you loved about CyanogenMod.

There are two method of fixing this problem
See also :How to take nandroid backup

Method 1: Download ES File Explorer

ES File Explorer File Manager allows you to manage your all kind of files easily on your Android tablet or phone. The default inbuilt gallery of Android isn't a good solution to access and manage files and you need a third-party powerful file management solution to manage files stored on the SD card of your device and on the internal storage.

ES File Explorer File Manager is a feature-rich solution to manage files on the go. Some cool features of this amazing app are listed below:
Download ES File Explorer

See also :How to Root official Lineage OS rom Easily

Method 2: Through TWRP Recovery.

It has been reported that deleting the '.android_secure' folder on the external sdcard (eg. via twrp) fixes the issue. 

So you have to boot into TWRP recovery and then delete this '.android_secure' folder from there then reboot your device.

This will do the trick if this still not works then follow below method.

Within the app I managed to rename android_secure folder and now I can access from the bookmark page as it should normally.
To rename the folder I had to access /mnt/media_rw/77B8-1D11 instead of the not working /storage/77B8-1D11

after renaming android_secure all is working ok.